WASHINGTON (REUTERS) - President Barack Obama will nominate attorney Jeh Johnson on Friday to be the next secretary of the Department of Homeland Security, a White House official said on Thursday.

Mr Johnson, who served as a top official in the Department of Defense, would succeed Ms Janet Napolitano, who stepped down earlier this year.

"He is one of the most highly qualified and respected national security leaders, having served as the senior lawyer for the largest government agency in the world," the official said of Mr Johnson.